Can you hear me now? The US Air Force is working on plans to improve radio communication over long distances by detonating plasma bombs in the upper atmosphere using a fleet of micro satellites.
Since the early days of radio, we’ve known that reception is sometimes better at night. Radio stations that cannot be picked up by day may be heard clearly at night, transmitting from hundreds of kilometres away.
This is down to changes in the ionosphere, a layer of charged particles in the atmosphere that starts around 60 kilometres up. The curvature of Earth stops most ground-based radio signals travelling more than 70 kilometres without a boost.
But by bouncing between the ionosphere and the ground they can zigzag for much greater distances. At night the density of the ionosphere’s charged particles is higher, making it more reflective.